It's been discussed extensively in this thread.
T-cell immunity is all that matters when it comes to population herd immunity from endemic respiratory viruses. T-cell immunity, or innate immunity governs B-cell recall. B-cells are the immune systems factories, they produce the neutralising antibodies that protect you from all of nature's pathogens. When you recover from a viral infection, or when you're vaccinated with vaccines that actually work, you will typically see a gradual depletion of circulating antibodies over the course of many months and years. Eventually antibody levels will drop below serconversion levels, i.e. there are not enough circulating antibodies to reliably protect you when challenged by a virus. But it doesn't matter, the immune system has a miraculous ability to 'remember' past exposure and when challenged by the same virus, even with a depleted antibody store, your B-cells will immediately begin to produce the neutralising antibodies which will either prevent infection altogether or vastly reduce the severity of any disease in the instances where it cannot.
What we're seeing with the vaccines is the immune system producing vast amounts of antibodies, the titres are insanely high immediately after dosing, to deal with the initial hit of spike. But then something unexpected happens, the antibody levels crash at a precipitous compounding rate, instead of the gradual decline we see in the recovered. Why? It would appear that the immune system does not recognise the spike as a pathogen rather as a toxin and so does not see the need to continue to produce antibodies. There is a condition in susceptible individuals who are administered Heparin, an anti-coagulant, where the immune system is triggered in a similar way but resolves over a couple of months with no long term immune memory of the event. That's likely the best case scenario for the not vaccines, a short term hit that has some protective effect and provides individual benefit against severe disease but back to square one after a few weeks or months. Roll your sleeve up for the next booster. How likely is this? Unknown. The crashing titres strongly suggest that little to no B-cell recall is present, but we can't be sure and it may vary between individuals.
OAS, original antigenic sin, is when the innate immune system relies on a previous disease exposure or vaccine when dealing with a mutated virus and is unable to produce the needed neutralising antibodies to fight the infection. It's relatively rare, the immune system relies on multiple types of neutralising antibodies when dealing with invading pathogens, but it does happen particularly when it's relying on a very narrowly based recall. The vaccines stimulate only 1 protein chain found in Covid, the data from the UK now confirms that when infected the double jabbed, well at least those never previously exposed to the virus, do not produce the other type of antibodies we would expect, in particular the n-antibodies that recognise the nucleocapsid component. Why does this matter if there are circulating S-protein antibodies from the vaccines? Well for a number of reasons. What happens when the vaccine derived antibodies drop below seroconversion levels? If there is B-cell recall from the vaccines what happens when Covid mutates past the spike antibodies? It's a head I lose tails I'm fucked scenario and we now know it's real.
OAS is not ADE, which is a whole different ballgame and let's all pray that isn't a thing. But OAS by itself will result in significantly higher mortality in the vaccinated. Either they'll need to have a lifetime of boosters to keep their antibody titres above seroconversion levels or hope that big pharma are able to roll out vaccine updates to deal with new variants.
